Genome-wide association study identified five quantitative trait loci and two candidate genes for digestive traits in Suhuai pigs.

This work aimed to identify markers and candidate genes underlying porcine digestive traits. In total, 331 pigs were genotyped by 80 K Chip data or 50 K Chip data. For apparent neutral detergent fiber digestibility, a total of 19 and 21 candidate single nucleotide polymorphisms (SNP) were respectively identified using a genome-wide efficient mixed-model association algorithm and linkage-disequilibrium adjusted kinship. Among them, three quantitative trait locus (QTL) regions were identified. For apparent acid detergent fiber digestibility, a total of 16 and 17 SNPs were identified by these two methods, respectively. Of these, three QTL regions were also identified. Moreover, two candidate genes (MST1 and LATS1), which are functionally related to intestinal homeostasis and health, were detected near these significant SNPs. Taken together, our results could provide a basis for deeper research on digestive traits in pigs.

Evolution of asexual Daphnia pulex in Japan: variations and covariations of the digestive, morphological and life history traits.

BACKGROUND: Several genetic lineages of obligate parthenogenetic Daphnia pulex, a common zooplankton species, have invaded Japan from North America. Among these, a lineage named JPN1 is thought to have started colonization as a single genotype several hundred to thousand years ago and subsequently produced many genotypes in Japan. To examine the phenotypic variations due to ecological drivers diverging the genotypes in new habitats, we measured heritability and variation in 17 traits, including life history, morphology and digestive traits, and the genetic distance among the D. pulex JPN1 genotypes in Japan. RESULTS: We found that most of the traits measured varied significantly among the genotypes and that heritability was highest in the morphological traits, followed by the digestive and life history traits. In addition, 93% of the variation in these traits was explained by the first three components in the principal component analysis, implying that variation of these heritable traits is not random but rather converged into a few directions. These relations among traits revealed the potential importance of predation pressures and food conditions as factors for diverging and selecting different genotypes. However, the magnitude of the difference in any single trait group did not correlate with the genetic distance. CONCLUSIONS: Our findings show that the divergent traits evolved within D. pulex JPN1 lineage without genetic recombination, since their ancestral clone invaded Japan. Large variations and covariations of the phenotypic traits, irrespective of the genetic distance among the genotypes, support the view that the invasive success of D. pulex JPN1 was promoted by a genetic architecture that allowed for large phenotypic variations with a limited number of functionally important mutations without recombination.

Phylogeny, body morphology, and trophic level shape intestinal traits in coral reef fishes.

Trait-based approaches are increasingly used to study species assemblages and understand ecosystem functioning. The strength of these approaches lies in the appropriate choice of functional traits that relate to the functions of interest. However, trait-function relationships are often supported by weak empirical evidence.Processes related to digestion and nutrient assimilation are particularly challenging to integrate into trait-based approaches. In fishes, intestinal length is commonly used to describe these functions. Although there is broad consensus concerning the relationship between fish intestinal length and diet, evolutionary and environmental forces have shaped a diversity of intestinal morphologies that is not captured by length alone.Focusing on coral reef fishes, we investigate how evolutionary history and ecology shape intestinal morphology. Using a large dataset encompassing 142 species across 31 families collected in French Polynesia, we test how phylogeny, body morphology, and diet relate to three intestinal morphological traits: intestinal length, diameter, and surface area.We demonstrate that phylogeny, body morphology, and trophic level explain most of the interspecific variability in fish intestinal morphology. Despite the high degree of phylogenetic conservatism, taxonomically unrelated herbivorous fishes exhibit similar intestinal morphology due to adaptive convergent evolution. Furthermore, we show that stomachless, durophagous species have the widest intestines to compensate for the lack of a stomach and allow passage of relatively large undigested food particles.Rather than traditionally applied metrics of intestinal length, intestinal surface area may be the most appropriate trait to characterize intestinal morphology in functional studies.